Have TV Questions? Ask a TV Technician
Does the power light on your TV turn off? How about the TV's sound? Is the backlight on your LCD panel pitch black or lit when the problem occurs? Were you successful with the firmware update (fully updated, then the TV reset without the TV shutting down midstream in the update process?)
Is the TV now stuck on at all times AFTER the software update? Pull the plug for 20 minutes if it is. Check it afterwards. See if the TV remote responds, and if it doesn't, manipulate the control on the TV itself, see if any response appears with that. You should find that joystick button on the bottom right.
I've seen this before. Unit locks up and can't even reboot itself. Keep in mind that 20 minute reset - works on everything from TVs to microwaves.
Thank you. Merry Christmas to you and your family too.